manuelbastioni add-on: hair library and clothes
I can answer your first question. You need to be using Manuel-Bastioni Lab 1.6 or higher. You must design a character and then finalize it (Finalize Tools), after which an ASSETS button appears. As of my writing hair is the only asset available. For best results choose hair with the same prefix as the human type you created. Press Load Element From Library. To fit it to the head you have to shift select the character's body mesh then look under Proxy Fitting to find and press Fit Proxy. I use the defaults with both options selected, but you can experiment in whatever context you later use the character. To change the hair colour use the Main Color node found in the Node Editor.